Thanks Pat I will shoot them an email. In the meantime, I was just wondering if other users have done this before. BTW, I do not have any Yagis for the 440 band at this time. I'm shopping and the Diamond is what I can afford.

I have two Cushcrafts for 70cm.One for SSB and one for the FM portion.The element lengths are about 3/16" difference between the two.I have tried to pull the FM unit down to the lower half but the SWR still won't go near flat but in the usefull range of 2 to 1.At these frequencies the adjustment of the Gamma match is very critical and sensitive to the antenna's surroundings so you need to make the adjustments loose enough to be able to 'bump' them with a long wooden dowel to keep out of the antenna's immediate field.The coax needs to be mounted as it will be when up and the height to test the match needs to be well up as much as 20 feet to have a chance to end up with a decent match when in place.Good luck..

Good points. I do plan on running two in phase vertically with a cross boom.

I also see your points about the gamma. It's hard to see the picture but it appears that the Diamond's matching system is concealed. That's my main reason for posting the question. Otherwise I would have no problem making adjustments. Never really thought about element spacing being that crucial for a 5 MHZ adjustment. Something to investigate.

Building one is also an option. The design that WB6BYU describes seems simple enough.

I don't think you'll see any of the reputable antenna manufacturers using gamma matches for VHF let alone UHF. The uneven element illumination results in squint and there is considerable common mode on the coax. Those problems were the inspiration behind the Quagi design.

Look at M Squared, Innov, Directive Systems etc to see how to properly drive a UHF antenna.

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